Intestinal Health and Nutrition in Critical Illness
Bacterial Translocation in Critical Illness
The intestinal barrier function relies on an intact mucus layer, lymphocytes and macrophages in the submucosa, Peyer’s patches, and IgA produced by the intestine. In critically ill patients, there is often decreased perfusion and oxygenation of the intestine. Thus, short periods of circulatory compromise may result in prolonged ischemia and hypoxia, causing cell damage, necrosis, loss of mucosal integrity, and barrier function loss, especially if associated with the prolonged absence of nutrients in the lumen.
Is Bacterial Translocation Important in Septic Patients?
There are no conclusive data on the cause-effect relationship between the failure of the intestine, bacterial translocation, and the development of sepsis.
Pharmacotherapy and Immunonutrition
Pharmacotherapy is a substrate that is part of the nutrition of the human subject and may also have beneficial properties on the body not associated with its nutritional property (behaves like a drug). Synonyms: functional food.
Immunonutrition is employing pharmaco-nutritional support. Synonyms: Functional Nutrition, Nutrition-system specific.
Effects of Immunonutrition
- Increased protein synthesis in skeletal muscle
- Decreased protein catabolism
- Improved nitrogen balance
- Enhanced immune response
- Better healing
Glutamine
Glutamine is the most abundant circulating amino acid in the body. It plays a central role in intermediary metabolism, especially during hypermetabolism. It is found in skeletal muscle, liver, intestine, immune cells, and kidneys.
Key functions of glutamine:
- Maintenance of nitrogen transport
- Acid-base balance
- Energy source for immune cells
- Stimulates the growth of the gastrointestinal mucosa
- Indispensable for the functioning of GALT (Gut-Associated Lymphoid Tissue)
Omega-3 Fatty Acids and Inflammation
n-3 Polyunsaturated Fatty Acids (PUFAs) inhibit the production of PGE2, TXA2, LTB4, IL-1, and TNF in both healthy subjects and in subjects with inflammatory diseases (rheumatoid arthritis, inflammatory bowel disease). Treatment of Inflammatory Bowel Disease (IBD), such as Crohn’s disease and ulcerative colitis, with supplements or a diet enriched with n-3 PUFAs decreases the number of acute relapses and allows for lower doses of corticosteroids and nonsteroidal anti-inflammatory drugs.
Situations that Benefit from Omega-3 Supplementation
- Coronary artery disease
- Obesity
- Cancer
- Arthritis
- Psoriasis
- Inflammatory bowel disease
- Lupus erythematosus
- Multiple sclerosis
- Major depression
- Bipolar disorder
Vascular Effects of Monounsaturated Fatty Acids (MUFA)
- Decrease of the cytotoxicity of oxidized LDL and macrophages
- Inhibition of leukocyte adhesion
- Decreased platelet activation
- Inhibition of proliferation of smooth muscle cells
- Inhibition of nitric oxide action
Dietary Fiber
Main Actions of Dietary Fiber
- Modifies intestinal transit
- Decreases bacterial overgrowth
- Decreases bacterial translocation
- Source of short-chain fatty acids (SCFAs)
Functions of Short-Chain Fatty Acids
Regulation of colonocyte environment, energy source, proliferation stimulation, increased blood flow, trophic effect on the jejunum, increased blood flow, stimulation of the autonomic nervous system, increased hormone production (GI) (gastrin, enteroglucagon, peptide YY), employment in liver metabolism by other tissues, muscle, and the Central Nervous System (CNS).
Principal Short-Chain Fatty Acids
Acetate, propionate, butyrate.
Source of Short-Chain Fatty Acids
Colonic bacterial fermentation: dietary fiber is not degraded, soluble starch, simple carbohydrates are not absorbed.
Short-chain fatty acids are responsible for 70% of colonocyte energy consumption.